Treatment of artificial silk



Patented July 15, 1930 UNITED STATES PATENT OFFICE No Drawing.Application filed October 29, 1928, Serial No. 315,912, and in GermanyMarch 12, 1927.

The object of the present invention is a method of production of a moreflexible and less brittle artificial silk, especially prepared toprotect the silk against damage in working. The process includes thefollowing treatment. The artificial silk is spun and is then wound uponbobbins or the like or into centrifugals and, after being washed, butbefore further working, undergoes a treatment with oils, soap solutionor similar suitable mate'- ria s.

It is well known that when the artificial silk'filaments are passedthrough a setting bath and thence directly to bobbins 0r centrifugalmachines, these filaments are soft and somewhat gelatinous, and even thefirst chemical action is quite incomplete. It appears that the filamentmay (at this stage) consist of a casing of precipitated cellulosehydrate inclosing a core of unreacted viscose, and it is further wellknown that the filaments a very slight strength at this stage, they arenot brittle and do not break from bending.

owever, after the reactions have been completed, the filaments are muchharder and after drying (even incomplete drying) they are quite brittle.In the industry, it is not usual to refer to the product as threadsuntil after the hardening is complete and the product dried. It is thisbrittleness which causes a great amount of breakage duringthe subsequentmechanical treatment.

Hereinafter, I use the term prior to any mechanical treatment todesignate the stage of the raw filaments as they occur on the origilialbobbin or in the centrifugal to which the filaments dome, direct fromthe setting bath, and before drying of the said filaments. During thesubsequent working of artificial silk, spun on bobbins or the like,there is often noticed the drawback that in mechanically 7 working thefine capillary threads, for instance in twisting and winding, theyeasily break, since they cannot stand the strains incident to drawingbecause of a certain brittle-. ness of the material. It is a well knownfact that in the textile industry many methods and nconvenience.

apparatuses have been used to counteract this For instance, theso-called paraffining of the twisted yarns or threads has been proposed.Also other means have been employed as an attempt to make finishedthreads soft and flexible. All these well known methods, however, referonly to finished yarns or threads, as are alreadyprepared for use byweavers, knitters, etc. (fabricating operations).

the present invention aims at somethlng quite different. It will protectthe artificial silk filaments spun onthe bobbins or the like,immediately after it has been spun and the chemicals sticking to itcleared oil", 1. e., before it undergoes further manipulations in themanufacturing of artificial silk yarn, as for instance twisting,winding, etc., (herein referred to as mechanical treatment) againstpossible damages occurring in the course of the aforesaid steps, as wellas in the fabricatingoperations and further working. This is suitablydone by treating the silk filaments, for example on said bobbins, withoil or an emulsion of oil or oil solution or soap solution and the likemeans for the purpose, such treatment being referred to generically asoiling the filaments. Thereby the artificial silk thread becomes softand flexible, and capable of withstanding the possibilities of breakingand similar damage in the course of further treatment such as mechanicaltreatment and fabricatingoperations. Ithasbeendemonstrated by tests thatartificial silk treated accordin to this invention, and similarartificial. sil that has not undergone this treatment, showed aconsiderable diflerence in the per centage of salable products. Whilethe silk treated according to the stated invention shows practically nobreaking of the capillary threads (filaments) there appears aconsiderable amount of such capillary breaks in the silk that had notundegone this treat- 95 ment. The finer the count of the variouscapillary threads, the more conspicuous is this difference, whereas withthe heavier counts it is less noticeable. The working of this method inactual prac- 100 tice may for instance,

be carried out as follows :The artificial silk, spun on perforatedbobbins or into centrifugals undergoes, immediately after the adheringchemicals have been washed oii', a treatment as described in the Germanpatent application 13.115485 VII/8a., filed September 2, 1924,corresponding U. S. Patent application Serial No. 44,079 filed July 16,1925, with the difference however, that instead of the washing liquid astherein stated, an oil or soap solution is used. As discharge anysu'table textile oil can be used-the strength of the solution can bechosen according to the degree of suppleness (flexibility) wished for.Soap solutions or oil emulsions and similar suitable means can be usedwith equal success. Instead of the process mentioned in said earlierpatent application, also other modes 0 applying the oily material may beused. The soap solutions and oil emulsions as referred to may begenerically included in the expression aqueous vehicle carrying an oilymaterial, all as a freely liquid mixture.

The lubricating (softening) liquid can also for instance be dischargedby pressure through the layers of the threads from the inside to theoutside of the perforated bobbins or the cakes while in thecentrifugals. The bobbins with the washed and if required or the sotreated cakes may also be immersed in the lubricating liquid or thelubricating liquid may e sprayed on them.

I claim In the treatment of artificial silk, the herein described stepof oiling the same by the use of an aqueous vehicle carrying an oilymaterial, all as a freely liquid mixture at a stage of the process notlater than while the silk is still wound upon a bobbin or into acentrifugal or the like just after forming the artifi cial filaments andbeing washed. 7

In testimony whereof I have signed my name to this specification.

BENNO BORZYKOWSKI.

